1. Field of the Invention
The present invention relates to a bicycle with an auxiliary power unit intended to improve stability for the positioning of a sensor used for detecting a pedaling torque.
2. Description of Background Art
A magnetostrictive torque sensor is known that is disposed adjacent to a hollow member on an outer periphery of a crankshaft in order to detect a pedaling torque applied by a rider. More specifically, as disclosed in Japanese Patent No. 3499138, a magnetic film is fixed to an outer peripheral surface of a hollow member on an outer periphery of a crankshaft with a magnetostrictive torque sensor is fixed on a casing side so as to face the magnetic film.
In addition, as disclosed in Japanese Patent No. 3642364, a magnetic film is fixed to an outer peripheral surface of a hollow torque transmitting member on an outer periphery of a crankshaft with a magnetostrictive torque sensor is disposed so as to face the magnetic film. The magnetostrictive torque sensor is disposed between the hollow torque transmitting member and an auxiliary power unit casing.
However, in the related art disclosed in Japanese Patent No. 3499138, the hollow member that produces magnetostriction is rotatably supported by a plurality of bearings relative to the casing and the magnetostrictive torque sensor is fixed to the casing side. This causes the magnetostrictive torque sensor and the magnetic film to be misaligned in a thrust direction, which makes it difficult to stabilize the position of the magnetostrictive torque sensor relative to the magnetic film.
In the related art disclosed in Japanese Patent No. 3642364, the magnetostrictive torque sensor is supported between the hollow torque transmitting member and the auxiliary power unit casing. It is nonetheless likely that the magnetostrictive torque sensor and the magnetic film will be misaligned in a thrust direction, so that the magnetostrictive torque sensor is not sufficiently stable relative to the position of the magnetic film.